// pandora.base64.js

// Exports the strToBase64 and base64ToStr functions

(function () {

  "use strict";

  /*\
  |*|
  |*|  Base64 / binary data / UTF-8 strings utilities
  |*|
  |*|  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Base64_encoding_and_decoding
  |*|
  \*/

  /* Array of bytes to base64 string decoding */

  function b64ToUint6 (nChr) {

    return nChr > 64 && nChr < 91 ?
        nChr - 65
      : nChr > 96 && nChr < 123 ?
        nChr - 71
      : nChr > 47 && nChr < 58 ?
        nChr + 4
      : nChr === 43 ?
        62
      : nChr === 47 ?
        63
      :
        0;

  }

  function base64DecToArr (sBase64, nBlocksSize) {

    var
      sB64Enc = sBase64.replace(/[^A-Za-z0-9\+\/]/g, ""), nInLen = sB64Enc.length,
      nOutLen = nBlocksSize ? Math.ceil((nInLen * 3 + 1 >> 2) / nBlocksSize) * nBlocksSize : nInLen * 3 + 1 >> 2, taBytes = new Uint8Array(nOutLen);

    for (var nMod3, nMod4, nUint24 = 0, nOutIdx = 0, nInIdx = 0; nInIdx < nInLen; nInIdx++) {
      nMod4 = nInIdx & 3;
      nUint24 |= b64ToUint6(sB64Enc.charCodeAt(nInIdx)) << 18 - 6 * nMod4;
      if (nMod4 === 3 || nInLen - nInIdx === 1) {
        for (nMod3 = 0; nMod3 < 3 && nOutIdx < nOutLen; nMod3++, nOutIdx++) {
          taBytes[nOutIdx] = nUint24 >>> (16 >>> nMod3 & 24) & 255;
        }
        nUint24 = 0;

      }
    }

    return taBytes;
  }

  /* Base64 string to array encoding */

  function uint6ToB64 (nUint6) {

    return nUint6 < 26 ?
        nUint6 + 65
      : nUint6 < 52 ?
        nUint6 + 71
      : nUint6 < 62 ?
        nUint6 - 4
      : nUint6 === 62 ?
        43
      : nUint6 === 63 ?
        47
      :
        65;

  }

  function base64EncArr (aBytes) {

    var nMod3 = 2, sB64Enc = "";

    for (var nLen = aBytes.length, nUint24 = 0, nIdx = 0; nIdx < nLen; nIdx++) {
      nMod3 = nIdx % 3;
      if (nIdx > 0 && (nIdx * 4 / 3) % 76 === 0) { sB64Enc += "\r\n"; }
      nUint24 |= aBytes[nIdx] << (16 >>> nMod3 & 24);
      if (nMod3 === 2 || aBytes.length - nIdx === 1) {
        sB64Enc += String.fromCharCode(uint6ToB64(nUint24 >>> 18 & 63), uint6ToB64(nUint24 >>> 12 & 63), uint6ToB64(nUint24 >>> 6 & 63), uint6ToB64(nUint24 & 63));
        nUint24 = 0;
      }
    }

    return sB64Enc.substr(0, sB64Enc.length - 2 + nMod3) + (nMod3 === 2 ? '' : nMod3 === 1 ? '=' : '==');

  }

  /* UTF-8 array to DOMString and vice versa */

  function UTF8ArrToStr (aBytes) {

    var sView = "";

    for (var nPart, nLen = aBytes.length, nIdx = 0; nIdx < nLen; nIdx++) {
      nPart = aBytes[nIdx];
      sView += String.fromCharCode(
        nPart > 251 && nPart < 254 && nIdx + 5 < nLen ? /* six bytes */
          /* (nPart - 252 << 30) may be not so safe in ECMAScript! So...: */
          (nPart - 252) * 1073741824 + (aBytes[++nIdx] - 128 << 24) + (aBytes[++nIdx] - 128 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
        : nPart > 247 && nPart < 252 && nIdx + 4 < nLen ? /* five bytes */
          (nPart - 248 << 24) + (aBytes[++nIdx] - 128 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
        : nPart > 239 && nPart < 248 && nIdx + 3 < nLen ? /* four bytes */
          (nPart - 240 << 18) + (aBytes[++nIdx] - 128 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
        : nPart > 223 && nPart < 240 && nIdx + 2 < nLen ? /* three bytes */
          (nPart - 224 << 12) + (aBytes[++nIdx] - 128 << 6) + aBytes[++nIdx] - 128
        : nPart > 191 && nPart < 224 && nIdx + 1 < nLen ? /* two bytes */
          (nPart - 192 << 6) + aBytes[++nIdx] - 128
        : /* nPart < 127 ? */ /* one byte */
          nPart
      );
    }

    return sView;

  }

  function strToUTF8Arr (sDOMStr) {

    var aBytes, nChr, nStrLen = sDOMStr.length, nArrLen = 0;

    /* mapping... */

    for (var nMapIdx = 0; nMapIdx < nStrLen; nMapIdx++) {
      nChr = sDOMStr.charCodeAt(nMapIdx);
      nArrLen += nChr < 0x80 ? 1 : nChr < 0x800 ? 2 : nChr < 0x10000 ? 3 : nChr < 0x200000 ? 4 : nChr < 0x4000000 ? 5 : 6;
    }

    aBytes = new Uint8Array(nArrLen);

    /* transcription... */

    for (var nIdx = 0, nChrIdx = 0; nIdx < nArrLen; nChrIdx++) {
      nChr = sDOMStr.charCodeAt(nChrIdx);
      if (nChr < 128) {
        /* one byte */
        aBytes[nIdx++] = nChr;
      } else if (nChr < 0x800) {
        /* two bytes */
        aBytes[nIdx++] = 192 + (nChr >>> 6);
        aBytes[nIdx++] = 128 + (nChr & 63);
      } else if (nChr < 0x10000) {
        /* three bytes */
        aBytes[nIdx++] = 224 + (nChr >>> 12);
        aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
        aBytes[nIdx++] = 128 + (nChr & 63);
      } else if (nChr < 0x200000) {
        /* four bytes */
        aBytes[nIdx++] = 240 + (nChr >>> 18);
        aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
        aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
        aBytes[nIdx++] = 128 + (nChr & 63);
      } else if (nChr < 0x4000000) {
        /* five bytes */
        aBytes[nIdx++] = 248 + (nChr >>> 24);
        aBytes[nIdx++] = 128 + (nChr >>> 18 & 63);
        aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
        aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
        aBytes[nIdx++] = 128 + (nChr & 63);
      } else /* if (nChr <= 0x7fffffff) */ {
        /* six bytes */
        aBytes[nIdx++] = 252 + (nChr >>> 30);
        aBytes[nIdx++] = 128 + (nChr >>> 24 & 63);
        aBytes[nIdx++] = 128 + (nChr >>> 18 & 63);
        aBytes[nIdx++] = 128 + (nChr >>> 12 & 63);
        aBytes[nIdx++] = 128 + (nChr >>> 6 & 63);
        aBytes[nIdx++] = 128 + (nChr & 63);
      }
    }

    return aBytes;

  }

  function strToBase64 (strInput) {
    if (typeof strInput !== 'string')
      throw new TypeError('The input should be a string')

    return base64EncArr(strToUTF8Arr(strInput))
  }

  function base64ToStr (base64Input) {
    if (typeof base64Input !== 'string')
      throw new TypeError('The input should be a string')

    return UTF8ArrToStr(base64DecToArr(base64Input))
  }

  // Export the functions to the global scope
  if (window) {
    if (!window.strToBase64)
      window.strToBase64 = strToBase64
    if (!window.base64ToStr)
      window.base64ToStr = base64ToStr
  }
}) ()